This invention relates generally to processes for manufacturing semiconductor integrated circuits.
In a variety of different processes, it may be desirable to form what is called a hard mask. A hard mask is a mask that may be utilized as an etching mask for subsequent process steps. For example, in the damascene process, a hard mask may be formed that prevents etched vias from extending through the hard mask. The hard mask may be utilized to enable an unlanded via integration scheme.
One problem with hard masks is that they may require an extra processing step. Basically, a separate hard mask may be deposited on top of a previously deposited material, such as a low dielectric constant film. The use of such hard mask may increase etch complexity due to the nature of the stack, including the resist, hard mask and underlying film. In addition, moisture may infiltrate through the hard mask. The infiltrated moisture, for example, may increase the capacitance contributed by a low dielectric constant film.
Thus, there is a need for better ways to form a hardmask.